Breast cancer is one of the most common forms of cancer and a leading cause of cancer death. Breast cancer screening has been recommended for many decades and several large scale studies have demonstrated a clear benefit to screening, particularly for women over the age of fifty. The combination of early detection and improved therapy has resulted in a significant reduction in breast cancer mortality.
Despite the success of screening mammography, it is also recognized as a less than ideal screening method. The limitations of mammography are particularly evident in women with mammographically dense breasts. The reduced sensitivity of mammography with increasing mammographic density is compounded by the fact that increased breast density is a significant risk factor for breast cancer.
One method for improved breast cancer screening is molecular breast imaging (MBI). In this method, a single-photon radiopharmaceutical, such as Tc-99m sestamibi, is administered to a subject and the subject's breast is compressed between two small gamma camera detectors. Radiation emitted by the single-photon radiopharmaceutical is then detected by collimation. Though MBI has been shown to have a high sensitivity to small lesions, its application in routine breast cancer screen is limited by the radiation dose associated the radiotracer agent. A variety of radiotracers may be used for MBI, but all of these radiopharmaceuticals deliver a radiation burden that is an order of magnitude larger than that delivered to a patient from a screening mammograph. Further, radiation dose reduction by simply reducing the amount of radiopharmaceutical administered to the subject can lead to reduced image quality, since fewer photons strike the gamma cameras.
It would therefore be desirable to have a system and method for reducing subject radiation exposure in MBI without causing a significant reduction in image quality.